An image forming apparatus includes a printing unit, first and second stacking units, first and second conveyance units, and a control unit. When the first conveyance unit conveys a sheet to the first stacking unit, the printing unit prints an image on a first number of sheets as first sheets in a first printing operation and prints the image on the first sheets in a second printing operation. When the second conveyance unit conveys the sheet to the second stacking unit, the printing unit prints the image on a second number of sheets, greater than the first number of sheets, as second sheets in the first printing operation and prints the image on the second sheets in the second printing operation. A number of sheets printed per unit time in the second printing operation is less than a number of sheets printed per unit time in the first printing operation.

An image forming apparatus includes a reverse roller pair including a drive roller and a driven roller by which a recording medium is nipped and conveyed reversibly, a motor configured to rotate the drive roller reversibly, a conveyance roller pair, a detection unit configured to detect the recording medium conveyed by the conveyance roller pair, and a controller configured to control the motor, in a case in which the recording medium is detected by the detection unit, to cause the drive roller to rotate in a first rotation direction by a first rotation amount, thereafter to cause the drive motor to rotate in a second rotation direction by a second rotation amount. A difference between the first rotation amount and the second rotation amount is set to an integer multiple of a predetermined rotation amount of the motor, the predetermined rotation amount making the drive roller one rotation.

An image forming apparatus includes a cover portion and an auxiliary tray. The cover portion is displaced between a closing position for closing the supply port and an opening position for opening the supply port. The auxiliary tray is attached to a sheet stack surface of the cover portion, and supports the sheet, together with the cover portion at the opening position. The auxiliary tray is, either in a first attachment state or in a second attachment state, attached to the cover portion. In the first attachment state, a longitudinal direction of the auxiliary tray extends along a width direction that crosses a sheet insertion direction and the auxiliary tray is stored in the sheet stack surface. In the second attachment state, the longitudinal direction extends along the sheet insertion direction, and the auxiliary tray extends out from the cover portion toward an upstream in the sheet insertion direction.

An image forming device includes an image forming unit, a roller unit, a static elimination brush, a moving unit, and a control unit. The static elimination brush eliminates static electricity of the printing medium. The moving unit moves the static elimination brush between a first position that does not intersect a first conveyance path on a downstream side of the roller unit in the conveyance path and a second position that intersects the first conveyance path. The control unit controls the moving unit during the conveyance of the printing medium, positions the static elimination brush at a position different from the second position until a front end of the printing medium passes an intersection position at which the static elimination brush and the first conveyance path intersect if the static elimination brush is positioned at the second position, and moves the static elimination brush to the second position after the front end of the printing medium passes the intersection position until a rear end of the printing medium passes the intersection position.

An image forming apparatus includes plural photosensitive members, a scanner unit for scanning the photosensitive members, and a fixing unit for fixing toner images. The scanner unit includes a rotatable polygonal mirror for reflecting laser beams emitted in correspondence to respective photosensitive members, reflecting members for reflecting the laser beams, and a box for accommodating the polygonal mirror and the reflecting members. The box includes plural outlets for the laser beams. Of the reflecting members, first and second reflecting members reflect laser beams toward corresponding first and second outlets respectively positioned farthest from and closest to the fixing unit. A distance between the first outlet and its corresponding photosensitive member is longer than a distance between the second outlet and its corresponding photosensitive member, whereas a distance between the first reflecting member and the polygonal mirror is shorter than a distance between the second reflecting member and the polygonal mirror.

An image forming apparatus includes a photosensitive drum, a light exposure device, a developing device, a fixing unit disposed opposite to the light exposure device relative to the developing device, a sheet supply tray disposed below the developing device, an ejection tray disposed above the developing device and having a sheet receiving surface inclined downward, relative to a horizontal direction, toward the charger, and a sheet conveying path through which a sheet is conveyed from the sheet supply tray to the ejection tray. A lowest end portion of the sheet receiving surface is disposed below an upper end of the charger in the vertical direction. The charger is disposed opposite to the developing device relative to the lowest end portion of the sheet receiving surface.

A drive transmission device includes a drive train including a plurality of drive transmitters, and a container. The plurality of drive transmitters of the drive train transmit a driving force of a drive source to a rotator rotatable around a shaft and a swing member rotatable around a shaft different from the shaft of the rotator. The container contains the drive train.

A post-processing apparatus includes a conveyance unit, a discharge port, a tray, an elevation unit, a detection unit, and a control unit. The conveyance unit conveys a print medium supplied from an image forming apparatus. The discharge port discharges the print medium conveyed by the conveyance unit. The tray is stacked with the print medium discharged from the discharge port and can be raised and lowered in a vertical direction. The elevation unit raises and lower the tray in the vertical direction. The detection unit detects a top surface of an uppermost print medium of one or more sheets of print media stacked on the tray. The control unit controls the conveyance unit and the elevation unit and hold a relative position of the top surface with respect to the discharge port if the print medium is discharged from the discharge port at a first position. The control unit causes the conveyance unit to convey the print medium at a first speed if a discharge time from a first timing indicating the timing relating to discharge of the print medium from the discharge port to a second timing indicating the timing when the print medium is detected by the detection unit is a first time and causes the conveyance unit to convey the print medium at a second speed different from the first speed if the discharge time is a second time.

An image forming apparatus includes an apparatus body and a moveable unit. The apparatus body includes an image forming device and a restriction portion. The moveable unit includes an image reading device and is detachably attached to the apparatus body. The moveable unit is opened and closed with respect to the apparatus body by rotation about a rotation shaft when the moveable unit is attached to the apparatus body. The moveable unit is attached to and detached from the apparatus body by moving in an axial direction of the rotation shaft. The moveable unit further includes a restricted portion that engages with the restriction portion that restricts a movement of the moveable unit in the axial direction. The restriction portion or the restricted portion further includes a deformation portion having elasticity. The deformation portion is deformed so that the moveable unit is attached to and detached from the apparatus body.

An image forming system that is capable of forming an image onto a sheet on a basis of print image data including multiple image data items imposed in such a manner as to be suitable for middle-folding and saddle-stitching and outputting a booklet by performing middle-folding and saddle-stitching includes: a storing unit that stores beforehand, as an output-processing content table, an inclination direction of a compilation tray onto which a stack of sheets that is to be subjected to imposition processing for pages or a facing page of the booklet and the middle-folding and saddle-stitching is placed; and a processing unit that generates the print image data by acquiring information of the inclination direction of the compilation tray, referencing to the output-processing content table, and performing the imposition processing.